Speed up QFile::copy on Darwin file systems that support cloning

Recent Darwin system have a new system call that allows cloning the
contents of a file from another one if the underlying file system (for
example, APFS) supports it.

Change-Id: I90ec53b8abd2b1dc4000070f295e226d0fb4c672
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

2 files changed, 20 insertions, 2 deletions

diff --git a/src/corelib/io/qfilesystemengine_unix.cpp b/src/corelib/io/qfilesystemengine_unix.cpp
index 40eadfb3e6..31353523ad 100644
--- a/src/corelib/io/qfilesystemengine_unix.cpp
+++ b/src/corelib/io/qfilesystemengine_unix.cpp
@@ -42,6 +42,7 @@
 #include "qfilesystemengine_p.h"
 #include "qfile.h"
 
+#include <QtCore/qoperatingsystemversion.h>
 #include <QtCore/qvarlengtharray.h>
 
 #include <stdlib.h> // for realpath()
@@ -66,6 +67,9 @@
 #endif
 
 #if defined(Q_OS_DARWIN)
+# if QT_DARWIN_PLATFORM_SDK_EQUAL_OR_ABOVE(101200, 100000, 100000, 30000)
+#  include <sys/clonefile.h>
+# endif
 // We cannot include <Foundation/Foundation.h> (it's an Objective-C header), but
 // we need these declarations:
 Q_FORWARD_DECLARE_OBJC_CLASS(NSString);
@@ -629,8 +633,22 @@ bool QFileSystemEngine::createLink(const QFileSystemEntry &source, const QFileSy
 //static
 bool QFileSystemEngine::copyFile(const QFileSystemEntry &source, const QFileSystemEntry &target, QSystemError &error)
 {
+#if QT_DARWIN_PLATFORM_SDK_EQUAL_OR_ABOVE(101200, 100000, 100000, 30000)
+    const auto current = QOperatingSystemVersion::current();
+    if (current >= QOperatingSystemVersion::MacOSSierra ||
+        current >= QOperatingSystemVersion(QOperatingSystemVersion::IOS, 10) ||
+        current >= QOperatingSystemVersion(QOperatingSystemVersion::TvOS, 10) ||
+        current >= QOperatingSystemVersion(QOperatingSystemVersion::WatchOS, 3)) {
+        if (::clonefile(source.nativeFilePath().constData(),
+                        target.nativeFilePath().constData(), 0) == 0)
+            return true;
+        error = QSystemError(errno, QSystemError::StandardLibraryError);
+        return false;
+    }
+#else
     Q_UNUSED(source);
     Q_UNUSED(target);
+#endif
     error = QSystemError(ENOSYS, QSystemError::StandardLibraryError); //Function not implemented
     return false;
 }
diff --git a/src/corelib/io/qfsfileengine.cpp b/src/corelib/io/qfsfileengine.cpp
index 0b9cd0557f..de921c0be6 100644
--- a/src/corelib/io/qfsfileengine.cpp
+++ b/src/corelib/io/qfsfileengine.cpp
@@ -860,9 +860,9 @@ bool QFSFileEngine::supportsExtension(Extension extension) const
 
 /*! \fn bool QFSFileEngine::copy(const QString &copyName)
 
-  For windows, copy the file to file \a copyName.
+  For Windows or Apple platforms, copy the file to file \a copyName.
 
-  Not implemented for Unix.
+  Not implemented for other Unix platforms.
 */
 
 /*! \fn QString QFSFileEngine::currentPath(const QString &fileName)